1. Field of the Invention
The present invention relates generally to fill blocks, sometimes referred to as manifolds, for providing connections between a compressed natural gas fuel system for a bus or other vehicle and a filling station where the vehicle is filled with fuel.
2. Description of the Prior Art
Typical prior art CNG fuel systems have utilized a multi-part fill block wherein many of the components such as the primary shutoff valve are separate components which are threadedly connected to the main fill block body. The fill block did not provide any means for defueling of the vehicle. All of the threaded connections on the fill block were NPT threads, that is tapered pipe threads.
Although these prior art fill block assemblies do satisfactorily perform their intended purpose, there is much room in the art for improvement of fill block designs to simplify their construction and to improve their performance.